The fiber is identified first
How a rug is cleaned follows from what it is made of, and the front of a rug does not tell you. The back does: hand-knotted rugs show the pattern in the knots, machine-made rugs show a uniform grid, and tufted rugs show a fabric backing glued on. Wool feels different from viscose between finger and thumb, and both feel different from polypropylene.
Water volume, pH, heat and agitation all change with the fiber. Wool is a protein and reacts badly to alkaline solutions. Viscose loses strength as soon as it is wet. Polypropylene tolerates most methods and holds oily soil stubbornly. Using one method on every rug is how rugs are ruined.
The dye test
A small amount of solution is applied to a white cloth and pressed against the pile in a hidden corner, under where the sofa sits or at the fringe end. If color transfers to the cloth, the dyes are not stable and the method changes: less moisture, faster extraction, and sometimes a different product.
Red and indigo next to cream is the classic risk. So is an older rug that has been cleaned badly before, because a previous bleed leaves the dye more mobile than it started.
Most faded rugs are dusty
A rug held vertically and struck produces a cloud of dust. That dust has worked down between the fibers rather than sitting on the surface, and it is why a rug that was vivid when it arrived now looks muted and slightly grey.
Light hitting a dusty pile scatters instead of reflecting off the dyed fiber, so every color reads a shade duller and the contrast in the pattern drops. Remove the dust and the pattern returns. The color was under the dust the whole time.
This is also why rugs are better cleaned on a schedule than when they begin to look dirty. By the time a rug looks dirty, the grit has been grinding at the base of the fibers for a long time.
Fringes, edges and the parts that wear first
Fringes are usually cotton even when the rug is wool, so they soil faster, hold that soil differently and turn grey while the rug still looks clean. They are cleaned separately and by hand.
Edges are where a vacuum never quite reaches, and a rug against a wall collects a dark line along that edge. Point these out when we arrive so nothing is missed.
Cleaning the floor under the rug
Every rug visit includes the floor under the rug. Grit that has worked through the pile sits on the hardwood and is ground into the finish underfoot, so the board under a hallway runner is often duller than the boards on either side. The floor is cleaned while the rug dries.
